Device for destruction-free inspection of a conveyor belt

ABSTRACT

A device for non-destructive inspection of a conveyor belt made from an elastomeric material has a carrying side for the goods to be conveyed, a running side, and an embedded strength support, whereby the conveyor belt is set in motion. A radiation source emits rays in the direction of the belt surface, which rays are so energy-rich that they pass through the conveyor belt, whereby a process computer evaluates the result of the irradiation test.

CROSS REFERENCE TO RELATED APPLICATIONS

Applicant claims priority under 35 U.S.C. §119 of German Application No.10 2004 061 367.2 filed Dec. 21, 2004. Applicant also claims priorityunder 35 U.S.C. §365 of PCT/DE2005/000731 filed Apr. 21, 2005. Theinternational application under PCT article 21(2) was not published inEnglish.

The invention relates to a device for destruction-free inspection of aconveyor belt made of elastomer material, having a carrying side for thegoods to be conveyed, and a running side, as well as having an embeddedstrength support, whereby the conveyor belt moves. With regard to thestrength support, a differentiation is made between steel rope conveyorbelts (St belts), textile conveyor belts (woven fabric belts), as wellas aramide conveyor belts (D belts).

Nowadays, destruction-free inspection of conveyor belts usually takesplace, in the case of steel rope belts, by means of magnet-inductivemethods, in which measurement values are recorded as part of apass-through method, which can provide indications for the presence ofirregularities in the interior of the belt. Carrying out these studiesand interpreting the test results cannot be done at the same time, andrequires specially trained personnel. The test results must besupplemented with X-ray images of the suspected locations of the belt,for a more precise damage analysis. These tests are performed by specialservice companies who also own the testing devices. The entire procedureis very complicated, particularly since the belts have to bedemagnetized again after the inspection.

There is no comparable method for textile belts or for aramide belts.Here, one must make do with an optical inspection of the surface, inwhich no information about the composition of the strength support isobtained, unless the damage is connected with a surface irregularity.The suggestion of monitoring the width of these belts by means ofmeasurement technology (DE 101 40 920 A1) and of presuming that aweakening of the strength support has occurred if the belt widthdecreases, because the belt has lengthened at this location and therebyalso reduced its width, has not yet been put into practice.

With regard to the state of the inspection technology for conveyorbelts, reference is made, in particular, to the document WO 03/059789A2.

With the background of the aforementioned problems, the task of theinvention now consists in making available a device, within theframework of the pass-through method, which guarantees destruction-freeinspection, independent of the type of strength support and thedimensions of the conveyor belt, which inspection makes any additionaltesting superfluous, while reducing the inspection time.

This task is accomplished, in accordance with the invention, in that aradiation source emits rays in the direction of the belt surface, whichrays are so energy-rich that they pass through the conveyor belt,whereby a process computer evaluates the result of the irradiation test.

Practical embodiments of the device are also according to the invention.

The invention will now be explained using a particularly advantageousexemplary embodiment, making reference to a schematic drawing.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an embodiment of the invention; and

FIG. 2 shows an enlarged portion of the conveyor belt.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The device comprises a support stand, particularly a transportablesupport stand 3, which is a four-sided support frame, whereby theconveyor belt 1 (e.g. St belt) runs moving within the support frame,with reference to the upper belt part, particularly within its lowerregion. The radiation source 4, which is connected with a control device12, is disposed on the upper part of the support frame, in thisconnection, and, in this connection, detects the entire width of thecarrying side of the conveyor belt in the material-free state. In thisconnection, the radiation source emits high-energy rays, particularly inthe form of X-rays or gamma rays. The gamma ray source is morecost-effective, in this connection, and can also be more easily adaptedto the explosion protection regulations (ATEX guideline) required inanthracite coal mining. It is particularly suitable for the inspectionof St belts. The use of an X-ray source, in turn, has the advantage thatthe energy of the rays being used can be adapted as needed, andtherefore is able to also inspect textile belts, in particular. Thesupport stand 3 or its direct vicinity is provided with a radiationprotection device.

A line sensor 5 with image processor is disposed on the support frame 3,below the running side of the conveyor belt 1, which sensor correspondswith the radiation source 4 that lies opposite. In this manner, the rayscan be bundled, in optimal manner, in terms of lines.

On one of the two side parts of the support frame 3, a defect markingsystem 13 is furthermore disposed, specifically in the region betweenthe carrying side 17 and the running side 18 of the conveyor belt 1 asshown in FIG. 1. Furthermore, the defect marking system is coupled witha control device 14. The defect marking system can place a marking (e.g.a paint spot) on the belt if an irregularity or serious damage isdetected, making it possible to find the location on the belt again,quickly and easily. In addition, the radiation source 4 corresponds withthe defect marking system 13.

In connection with the radiation source 4, the line sensor 5 with imageprocessor, and the defect marking system 13, the following additionalmeasures can advantageously be used.

Two start markings 6 comprise, i.e. delimit a finite segment 19 of theconveyor belt 1. The length of each segment is 10 m to 500 m,particularly under the aspect of equal lengths, in each instance. Startmark 6 is situated at the two delimitations 20 as shown in FIG. 2.

With regard to the start marking 6, the following variants are used:

-   -   The start marking is formed by at least one notch, color strip,        reflection zone, metal particle, or permanent magnet.    -   The start marking is a code, particularly under the aspect of        mechanical, optical, magnetic, electrically conductive, or        radioactive detection. The code, in turn, is a bar code or is        structured similar to a bar code. Also, the code can consist of        small permanent magnets, particularly in the form of a serial        arrangement.

Detection of the start marking 6, in each instance, takes place by meansof a scanning unit, particularly in the form of a reader head 7, withoutcontact. In this connection, it is sufficient if a single scanning unitdetects all of the start markings.

Every finite segment is provided with a distinct address, so thatsegment marking is formed. The distinctness is produced by means ofsegment numbering (e.g. 1, 2, 3, etc.).

Here, the address of the segment marking is a transponder 8. Thescanning unit, which also performs the detection without contact,comprises an antenna 9 and a transponder reader 11. For the remainder,reference is made here to the general state of transponder technology.

The address of the segment marking can also detect those variants thatwere already mentioned in connection with the start marking 6, wherebythen the scanning unit is also a read head 7, preferably within theframework of a common detection system of start marking and segmentmarking.

The address of the segment marking as well as the start marking arelocated within the carrying side of the conveyor belt 1, in its edgeregion. In this connection, it is advantageous if the transponder, inparticular, is completely embedded in elastomer material. This alsoholds true when using a code, specifically in the form of a coded matrix(DE 100 17 473 A1).

The address of the segment marking and the start marking 6 are separatemarking systems here, whereby it is advantageous if the address of thesegment marking is situated in the vicinity of the start marking. Inthis connection, it is unimportant whether the address is disposed infront of or behind the start marking, with reference to the runningdirection of the conveyor belt.

According to one variant (not shown here), the address of the segmentmarking and the start marking 6 form a uniform marking system, forexample in the form of a code in stripe form. The common scanning unitis then a read head.

The precise location determination takes place using an encoder that isdriven by the conveyor belt 1 itself, for example by means of frictionwheel coupling. Within the framework of the exemplary embodimentpresented here, the encoder 10 is driven by way of the axle of anon-driven drum 2. The encoder produces a certain number of electricalpulses for a certain path distance. These pulses are acquired in theprocess computer 15 by means of a counter and, together with the segmentmarking and the address of the belt segment, yield precise location datafor every point of the conveyor belt to be inspected. The precision ofthe location determination depends on the selection of the encoder andthe precision of the determination of the segment marking, and can bevery high. Precision values of a few tenths of a millimeter arepossible.

The encoder can be, for example, a multi-pole encoder (DE 203 12 808 U1)or an optoelectronic encoder. In this regard, reference is made to thegeneral state of encoder technology.

The process computer 15 is coupled with the following device parts,namely with:

-   -   the radiation source 4 including its control device 12;    -   the line sensor 5 with image processor;    -   the defect marking system 13 including its control device 14;    -   the first and second scanning unit, within the framework of a        separate or common detection system, as well as    -   the encoder 10.

The process computer 15 in turn is connected with a monitor 16, so thatautomated image evaluation is possible.

REFERENCE SYMBOL LIST

-   1 conveyor belt-   2 non-driven drum (reversing or deflection drum)-   3 support stand (support frame)-   4 radiation source-   5 line sensor with image processor-   6 start marking (trigger marking)-   7 read head-   8 transponder-   9 antenna for transponder-   10 encoder-   11 transponder reader-   12 control device for radiation source-   13 defect marking system-   14 control device for defect marking system-   15 process computer (controller)-   16 monitor

The invention claimed is:
 1. An assembly comprising: (a) a movingconveyor belt made of elastomeric material and having a belt surface, acarrying side for goods to be conveyed, a running side, and an embeddedstrength support; (b) a device for non-destructive inspection of theconveyor belt, said device comprising a radiation source and a processcomputer; and (c) a defect marking system corresponding with theradiation source; said radiation source emitting rays toward the beltsurface to perform an irradiation test having a result, said rays beingsufficiently energetic to pass through the conveyor belt; and theprocess computer evaluating the result of the irradiation test; whereinthe process computer is coupled with the following device parts: theradiation source, by way of a radiation control device; a line sensorwith image processor; the defect marking system, by way of a defectmarking system control device; a first scanning unit and a secondscanning unit, and an encoder; wherein the entire conveyor belt isdivided into finite segments, whereby each segment is provided with adistinct address, so that segment marking occurs, whereby detection ofthe address of the segment marking, in each instance, takes placewithout contact, using the first scanning unit; and that the finitesegments are delimited by a start marking, in each instance, whereby thedetection of the start marking, in each instance, also takes placewithout contact, using the second scanning unit.
 2. The assemblyaccording to claim 1, wherein the radiation source emits X-rays or gammarays.
 3. The assembly according to claim 1, wherein the rays emitted bythe radiation source strike an entire width of the conveyor belt.
 4. Theassembly according to claim 1, wherein the rays emitted by the radiationsource strike the carrying side in a material-free state.
 5. Theassembly according to claim 1, wherein the radiation source isaccommodated in an upper part of a transportable support stand.
 6. Theassembly according to claim 5, wherein the support stand is a four-sidedsupport frame, whereby the conveyor belt runs within a lower region ofthe support frame.
 7. The assembly according to claim 5, wherein theradiation source is coupled with the radiation control device.
 8. Theassembly according to claim 7, wherein the radiation source correspondswith the line sensor with image processor that lies opposite, which isdisposed below the running side.
 9. The assembly according to claim 8,wherein the line sensor with image processor is disposed on the supportstand.
 10. The assembly according to claim 1, wherein the defect markingsystem is disposed laterally with regard to the conveyor belt in theregion between the carrying side and the running side.
 11. The assemblyaccording to claim 1, wherein the defect marking system is disposed on asupport stand.
 12. The assembly according to claim 1, wherein the finitesegments are divided at a distance of 10 to 500 m in length.
 13. Theassembly according to claim 1, wherein the address of the segmentmarking as well as an address of the start marking are located within anedge region of the carrying side.
 14. The assembly according to claim 1,wherein the address of the segment marking and an address of the startmarking are a part of separate marking systems.
 15. The assemblyaccording to claim 14, wherein the address of the segment marking is inthe vicinity of the start marking.
 16. The assembly according to claim1, wherein the address of the segment marking and an address of thestart marking form part of a uniform marking system.
 17. The assemblyaccording to claim 1, wherein the address of the segment marking is atransponder, whereby the first scanning unit comprises an antenna and atransponder reader.
 18. The assembly according to claim 1, wherein atleast one of the address of the segment marking and an address of thestart marking is formed by at least one notch, color strip, reflectionzone, metal particle, or permanent magnet.
 19. The assembly according toclaim 18, wherein the first and second scanning unit are a commondetection system.
 20. The assembly according to claim 1, wherein atleast one of the address of the segment marking and an address of startmarking is a code.
 21. The assembly according to claim 20, wherein thecode is a bar code.
 22. The assembly according to claim 20, wherein thecode comprises a serial arrangement of small permanent magnets.
 23. Theassembly according to claim 1, wherein the encoder is driven by theconveyor belt itself.
 24. The assembly according to claim 1, wherein theencoder is connected with a movable part of the conveyor belt.
 25. Theassembly according to claim 24, wherein the encoder is driven by way ofan axle of a non-driven drum.
 26. The assembly according to claim 1,wherein the process computer is coupled with a monitor.